Pre-expanded connector for expandable downhole tubulars

Abstract

A method and apparatus for providing an expandable threaded connection between segments of expandable tubulars. Threaded connections are machined into pre-expanded ends of tubulars. Once the threaded connections are machined into the pre-expanded ends, two joints of tubulars are connected using the threads, thus creating a pre-expanded threaded connection. After a tubular string is made up and lowered into a wellbore, the entire length of the string is expanded using known methods for expanding tubulars. During the downhole expansion operation, the pre-expanded threaded connections experience minimal expansion. The minimal downhole expansion of the pre-expanded threaded connections allows the threaded connections to maintain their sealing ability and coupling strength.

1. An expandable threaded tubular connection comprising:
 a first tubular segment with a pre-expanded end, the pre-expanded end including a pin member with threads; and 
 a second tubular segment with a pre-expanded end, the pre-expanded end including a box member with threads suitable for threadedly engaging said threads of said pin member of said first tubular segment, 
 wherein the first and second tubular segments, the pre-expanded ends, and the pin and box member threads are expanded after the expandable threaded tubular connection is made-up and inserted downhole, wherein a sealing ability and coupling strength of the expandable threaded tubular connection is not compromised by the expansion. 
 
   
   
     2. The expandable threaded tubular connection of  claim 1 , wherein the box member threads have been machined into the pre-expanded end of the second tubular segment, the box member threads being helical mating threads that are shaped and sized to mate with helical threads on the pin member. 
   
   
     3. The expandable threaded tubular connection of  claim 1 , wherein the pin member threads have been machined into the pre-expanded end of the first tubular segment, the pin member threads being helical threads extending substantially along the length of the pin member. 
   
   
     4. The expandable threaded tubular connection of  claim 1 , wherein the pre-expanded end of the first tubular segment and the pre-expanded end of the second tubular segment are expanded by inserting an expansion tool into the ends of the first tubular segment and the second tubular segment respectively to a predetermined length. 
   
   
     5. The expandable threaded tubular connection of  claim 1 , wherein the outside diameters of the pre-expanded ends of the first tubular segment and the second tubular segment are substantially equal to the API drift diameter of a host pipe into which the connection is lowered. 
   
   
     6. The expandable threaded tubular connection of  claim 1 , wherein the outside diameters of the pre-expanded ends of the first tubular segment and the second tubular segment are less than the API drift diameter of a host pipe into which the connection is lowered. 
   
   
     7. The expandable threaded tubular connection of  claim 1 , wherein the outside diameters of the pre-expanded ends of the first tubular segment and the second tubular segment are greater than the API drift diameter of a host pipe into which the connection is lowered. 
   
   
     8. The expandable threaded tubular connection of  claim 1 , wherein the outside diameter of the first and second tubular segments are expanded more than the outside diameter of the pre-expanded ends. 
   
   
     9. The expandable threaded tubular connection of  claim 1 , wherein the first tubular segment and the second tubular segment are radially expanded past their yield point. 
   
   
     10. The expandable threaded tubular connection of  claim 1 , further comprising a sealing material surrounding the expandable threaded tubular connection. 
   
   
     11. The expandable threaded tubular connection of  claim 1 , wherein the pre-expanded end of the first tubular segment and the pre-expanded end of the second tubular segment are stress relieved. 
   
   
     12. The expandable threaded tubular connection of  claim 1 , wherein the pre-expanded end of the first tubular segment and the pre-expanded end of the second tubular segment are heat treated. 
   
   
     13. The expandable threaded tubular connection of  claim 1 , wherein the entire length of the first tubular segment and the second tubular segment is heat treated. 
   
   
     14. The expandable threaded tubular connection of  claim 1 , wherein the first tubular segment constitutes the leading tubular in a string of tubulars inserted in a bore hole and has a reamer or drill bit connected to it. 
   
   
     15. The expandable threaded tubular connection of  claim 1 , wherein the first tubular segment and the second tubular segment are supplied by a tubular manufacturer with the pre-expanded ends already shaped and sized. 
   
   
     16. An expandable threaded tubular connection for well bore production tubulars comprising:
 a first expandable tubular segment with a first tapered end joint connected to the end of the first expandable tubular segment, wherein the first tapered end joint has been pre-expanded to a given shape and size by inserting an expansion tool into the first tapered end joint to a predetermined length, the first tapered end joint including a pin member with thread means; and 
 a second expandable tubular segment with a second tapered end joint connected to the end of the second expandable tubular segment, wherein the second tapered end joint has been pre-expanded to a given shape and size by inserting an expansion tool into the second tapered end joint to a predetermined length, the second tapered end joint including a box member with thread means suitable for threadedly engaging said pin member of said first tapered end joint; 
 wherein the shape and size of the first and second tapered end joints are selected such that the first and second tapered end joints, including the thread means of the first and second tapered end joints, are expanded less than the first and second expandable tubular segments after the expandable threaded tubular connection is inserted downhole; and 
 wherein said expandable threaded tubular connection maintains its sealing ability following expansion of the expandable threaded tubular connection after it has been inserted downhole. 
 
   
   
     17. The expandable threaded tubular connection of  claim 16  wherein the expansion tool used to expand the first tapered end joint and the second tapered end joint is an expansion mandrel. 
   
   
     18. The expandable threaded tubular connection of  claim 17  wherein the expansion mandrel includes a pilot section used to center the expansion mandrel within the first tapered end joint and the second tapered end joint. 
   
   
     19. The expandable threaded tubular connection of  claim 16  wherein the expansion tool is a rotary expansion tool. 
   
   
     20. The expandable threaded tubular connection of  claim 16  wherein the first tapered end joint and the second tapered end joint are made of a different material than the material of the first tubular segment and the second tubular segment. 
   
   
     21. The expandable threaded tubular connection of  claim 16  further comprising a sealing material surrounding the expandable threaded tubular connection. 
   
   
     22. An expandable threaded tubular connection for well bore production tubulars comprising:
 a first expandable tubular segment with a first tapered end joint connected to the end of the first expandable tubular segment, wherein the first tapered end joint is forged to a given shape and size such that the inner diameter of the first tapered end joint is greater than the inner diameter of the first expandable tubular segment, the first tapered end joint including a pin member with thread means; and 
 a second expandable tubular segment with a second tapered end joint connected to the end of the second expandable tubular segment, wherein the second tapered end joint is forged to a given shape and size such that the inner diameter of the second tapered end joint is greater than the inner diameter of the second expandable tubular segment, the second tapered end joint including a box member with thread means suitable for threadedly engaging said thread means of said pin member of said first tapered end joint; 
 wherein the shape and size of the first and second tapered end joints are selected such that the first and second tapered end joints, including the thread means of the first and second tapered end joints, are expanded less than the first and second expandable tubular segments after the expandable threaded tubular connection is inserted downhole; and 
 wherein said expandable threaded tubular connection maintains its sealing ability following expansion of the expandable threaded tubular connection after it has been inserted downhole. 
 
   
   
     23. An expandable threaded tubular connection for well bore tubulars comprising:
 a first expandable casing segment having a first tapered end joint, wherein the first tapered end joint is pre-expanded such that the inner diameter of the first tapered end joint is greater than the inner diameter of the remainder of the first expandable casing segment, the first tapered end joint including a pin member with thread means; and 
 a second expandable casing segment having a second tapered end joint, wherein the second tapered end joint is pre-expanded such that the inner diameter of the second tapered end joint is greater than the inner diameter of the remainder of the second expandable casing segment, the second tapered end joint including a box member with thread means suitable for threadedly engaging said thread means of said pin member of said first tapered end joint; 
 wherein the inner diameters of the first and second tapered end joints are selected to allow for less expansion of the end joints as compared to the expansion of the first and second expandable casing segments when the first and second expandable casing segments and first and second tapered end joints, including the thread means of the first and second tapered end joints, are expanded after the expandable threaded connection is made-up and inserted downhole. 
 
   
   
     24. An expandable threaded tubular connection for well bore tubulars comprising:
 a first expandable liner segment having a first tapered end joint, wherein the first tapered end joint is pre-expanded such that the inner diameter of the first tapered end joint is greater than the inner diameter of the remainder of the first expandable liner segment, the first tapered end joint including a pin member with thread means; and 
 a second expandable liner segment having a second tapered end joint, wherein the second tapered end joint is pre-expanded such that the inner diameter of the second tapered end joint is greater than the inner diameter of the remainder of the second expandable liner segment, the second tapered end joint including a box member with thread means suitable for threadedly engaging said thread means of said pin member of said first tapered end joint; 
 wherein the inner diameters of the first and second tapered end joints are selected to allow for less expansion of the end joints as compared to the expansion of the first and second expandable liner segments when the first and second expandable liner segments and first and second tapered end joints, including the thread means of the first and second tapered end joints, are expanded after the expandable threaded connection is made-up and inserted downhole.